TW202227259A - 3d printing set and method for 3d inkjet printing by using the same - Google Patents

Abstract

The present invention provides a method for 3D inkjet printing, which comprises: a preheating step: using an external heating source to heat a main body layer composed of a first composition to a first temperature, wherein the main body layer has a thickness of 10 μm to 500 μm and a unit density of 0.1 to 1.0 g/cm ³, and the first temperature is less than the melting point of the first composition; a heating step: a second composition is applied to the surface of the first composition at the first temperature of the composite to proceed an exothermic cross-linking polymerization, so that the main body layer is heated to a second temperature to become a molten state; and a cooling step: the main body layer in the molten state is cooled down and solidified to form.

Description

3D printing kit, and method of using the same for 3D inkjet printing

The present invention relates to three-dimensional printing technology, in particular to a 3D inkjet printing technology.

3D printing technology has excellent characteristics such as convenient rapid prototyping (RP), can reduce R&D costs, shorten R&D cycle, improve the success rate of new product development, and meet the needs of personal production and local manufacturing. Since the 1990s, 3D printing has continued to develop rapidly. Not only related technologies, devices, processes, and methods have been continuously innovated and made breakthroughs, but also 3D printing models and types have been continuously introduced. The size of printable items, output stability and other aspects have also been significantly improved. In the past ten years, the size of the 3D printing market has grown and expanded by leaps and bounds.

Basically, 3D printing technology is a technology that can automatically and quickly make complex-shaped design images into three-dimensional shapes without the use of tools, molds or fixtures, using the technical concept of stacking layers like building a pyramid. A rapid prototyping method for solid objects in three-dimensional shapes. In a nutshell, 3D printing is based on the principles of slicing, stacking, and additive manufacturing. The molding materials containing specific plastics, metals, etc. are dissolved, solvated, or melted, and then directly precise using 3D printing equipment. Inkjet prints on a plane, and then sintering, bonding, drying, and curing by light energy, electrical energy, and chemical energy to form XY-axis 2-dimensional plane layers, and then move in the Z-axis direction and position them accurately to stack them layer by layer. , and finally form a three-dimensional solid object with a three-dimensional shape.

At present, 3D printing methods are very diverse, for example, Fused Deposition Modeling (FDM; also known as Fused Filament Fabrication, FFM), Laminated Object Manufacturing (LOM), Digital Light Processing ( Digital Light Processing, DLP; also known as Film Transfer Imaging, FTI), stereolithography (Stereo-lithography Apparatus, SLA), glue curing jet printing (Plaster-based 3D printing or Powder bed and inkjet head 3D printing, 3DP), Three-dimensional molding methods such as Selective Laser Sintering (SLS) and Selective Laser Melting (SLM; or Direct Metal Laser Sintering, DMLS). In addition, Hewlett-Packaed Inc. published Multi Jet Fusion techology in 2014. This technology uses a hot bubble nozzle to spray a thermal catalyst for patterning. After being irradiated with infrared light, the thermal The catalyst is induced to release heat to melt the plastic powder at 200°C, becoming a 3D printing system that can directly melt plastic powder, and has both speed and precision.

However, most of the thermal catalysts used in the above-mentioned multi-jet melting technologies contain some dark light-absorbing substances, so most of the printed products are dark. If light-colored materials are used, energy absorption may be reduced. This leads to molding failure or prolonged molding time; in addition, the existing multi-jet melting technology can only produce physical cross-linking of 3D molding materials, so there is still insufficient mechanical strength. Therefore, how to develop a solution that can solve the above-mentioned shortcomings of the conventional technology is an urgent problem to be solved by those in the related technical field.

Therefore, the inventors of the present invention have developed a 3D inkjet printing method through intensive research and search for various possible solutions for solving the above-mentioned problems of the traditional technology, which is to rapidly spray the reactive fusion agent on the laminate Good preheating of the polymer powder printing area, while applying a near-infrared light heat source, triggers the cross-linking polymerization reaction between the reactive fusion agent and the polymer powder and releases a lot of heat, resulting in a synergistic effect, causing it to The temperature is higher than the melting point of the polymer powder, so the polymer powder can be melted and molded with a lower heat, and the mechanical strength of the finished product can be effectively improved through chemical cross-linking. The printing speed of the present invention is more than 10 times faster than that of the traditional 3D laser melting polymer powder technology, and objects with excellent mechanical properties can be completed in a short time, and the density and precision are equivalent to mold injection molding. More extensive, but can save the high cost of developing molds, and establish a new milestone for industrial product proofing and digital manufacturing. In addition, since the present invention uses the heat of chemical reaction to melt the polymer powder, the printing speed and quality will not be affected even if a light color material is added for printing.

That is, the present invention can provide a 3D inkjet printing method, which includes: a preheating step: using an external heating source to heat a body layer composed of a first composition to a first temperature; The thickness is between 10 μm and 500 μm, the unit density is between 0.1 and 1.0 g/cm ³ , and the first temperature is less than the melting point of the first composition; the heating step: at the first temperature, a second composition is Coating on the surface of the first composition to carry out cross-linking polymerization exothermic reaction, raising the temperature of the main body layer to a second temperature to become a molten state; and cooling step: cooling the main body layer in a molten state to cool down and solidify and form.

(Ⅰ)；

(Ⅱ)； 在上述化學式(Ⅰ)、(Ⅱ)中，R ₁、R ₂、R ₃、及R ₄係各自獨立地表示烷基或芳烴基。 According to an embodiment of the present invention, the first composition comprises at least a molding material, and the molding material is a compound A having a chemical structure represented by chemical formula (I), a compound having a chemical structure represented by chemical formula (II) Compound B, or polyamine compounds:

(I);

(II); In the above chemical formulae (I) and (II), R ₁ , R ₂ , R ₃ , and R ₄ each independently represent an alkyl group or an aromatic hydrocarbon group.

According to an embodiment of the present invention, the second composition comprises at least a compound C having O=C=N-functional group, and the weight ratio of the molding material to the compound C in the main body layer is 1: Between 1 and 10:1.

According to an embodiment of the present invention, the difference between the first temperature and the melting point of the first composition is between 10°C and 100°C.

According to an embodiment of the present invention, the second temperature is greater than the melting point of the first composition.

According to an embodiment of the present invention, the second composition further comprises at least one selected from a catalyst, a physical property modifier, a dispersant, a cosolvent, and a colorant.

According to an embodiment of the present invention, the 3D inkjet printing method wherein the catalyst is dibutyltin dilaurate (DBTDL).

According to an embodiment of the present invention, the physical property modifier is at least one selected from polyols, polyether polyols, polyester polyols, and combinations thereof.

According to an embodiment of the present invention, in the heating step, the second combination is performed by any one of a flat coating method, a sputtering method, a spray coating method, a casting coating method, a roll coating method, and a strip coating method. The material is coated on the surface of the first composition.

According to an embodiment of the present invention, the second composition further comprises at least one selected from a catalyst, a physical property modifier, a dispersant, a cosolvent, and a colorant.

According to an embodiment of the present invention, the catalyst is dibutyltin dilaurate (DBTDL).

According to an embodiment of the present invention, the physical property modifier is at least one selected from polyols, polyether polyols, polyester polyols, and combinations thereof.

Hereinafter, the embodiments of the present invention will be described and described in more detail by listing different specific embodiments, so as to make the spirit and content of the present invention more complete and easy to understand; however, those with ordinary knowledge in the art should understand that Of course, the present invention is not limited to these examples, and other same or equivalent functions and sequence of steps can also be utilized to achieve the present invention.

The foregoing and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of the embodiments with reference to the drawings. The directional terms mentioned in the following embodiments, such as: up, down, left, right, front or rear, etc., are only used to refer to the directions of the accompanying drawings. Therefore, these directional terms are only used to illustrate rather than limit the present invention, and the present invention can be implemented in any other manner.

First, please refer to FIG. 1 , which is a standard flow chart showing the high-speed 3D of the present invention. The method includes a preheating step S1 , a heating step S2 , and a cooling step S3 .

(Ⅰ)；

(Ⅱ)； In the preheating step S1, the first composition is uniformly layered by a roller to form a main body layer, and an external heating source is used to heat the main body layer to a first temperature. The first composition contains at least a molding material, and the molding material is a compound A with a chemical structure represented by the chemical formula (I), or a compound B with a chemical structure represented by the chemical formula (II), or a polyamine compound :

(I);

(II);

According to one aspect of the present invention, in the above chemical formulae (I) and (II), R ₁ , R ₂ , R ₃ , and R ₄ each independently represent an alkyl group or an aromatic hydrocarbon group. For example, the compound A can be a semi-crystalline polyamide, preferably polyamide-6 (PA-6), polyamide-66 (PA-66), polyamide-610 (PA-610 ), Polyamide-1010 (PA-1010), Polyamide-11 (PA-11), Polyamide-12 (PA-12), Polyamide-9 (PA-9), Polyamide- 612 (PA-612), polyamide-121 (PA-121), polyphthalamide (PPA), polyparaphenylene terephthalamide (PPTA); the compound B can be a polyurethane ( PU), preferably thermoplastic polyurethane (TPU).

Also, in one embodiment, the preferred examples of the polyamine compounds include at least one of linear aliphatic polyamines, branched chain aliphatic polyamines, and cyclic aliphatic polyamines; more preferably ethyl acetate Ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine , Diethylenetriamine (diethylenetriamine), 1,2-propanediamine (1,2-propanediamine), 1,4-diazepine, phenylenediamine (phenylenediamine).

On the other hand, the thickness of the main body layer is not particularly limited, and is generally between 10 μm and 500 μm; preferably between 10 μm and 300 μm; more preferably between 50 μm and 150 μm. In addition, the unit density of the main body layer is generally between 0.1g/cm ³ to 1.0g/cm ³ ; preferably between 0.2g/cm ³ to 0.9g/cm ³ ; most preferably between 0.4g/cm cm ³ to 0.6 g/cm ³ .

Next, the heating step S2 is to coat a second composition on the surface of the first composition at the first temperature, and the coating method can be a flat coating method, a sputtering method, a spraying method, a casting coating method, a roller Any of the coating method and the strip coating method; preferably, the second composition is sprayed onto the surface of the first composition by using a thermal bubble spray head or a piezoelectric spray head. The thermal-bubble nozzle or the piezoelectric nozzle can control the spraying range through the processing unit of the 3D printing device, thereby conforming to the patterns of a plurality of cross-sectional images of the three-dimensional object to be printed. When using a hot-bubble shower head, the viscosity of the second composition at room temperature is preferably below 4cps; and when using a piezoelectric shower head, the viscosity of the second composition at room temperature is preferably between 6 to 8cps, 19 to 23cps, or 30cps.

The second composition contains a functionally reactive fusion agent capable of chemically reacting with the first composition and releasing heat, so the cross-linking polymerization reaction will occur after the first composition contacts the second composition, The main body layer is heated to the second temperature to be in a molten state.

According to the technical idea of the present invention, the second composition at least includes a compound with O=C=N-functional group, especially a compound C with a chemical structure represented by chemical formula (III):

(III)

(III)

In the above chemical formula (III), R ₅ represents an alkyl group or an aromatic hydrocarbon group; for example, the compound C can be toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate Isocyanate (MDI), dicyclohexylmethane diisocyanate (H ₁₂ MDI), lysine diisocyanate (LDI).

In addition, compound C can also be HDI polyisocyanates, such as HDI isocyanurate trimer, such as triglycidyl isocyanurate (1,3,5-triazine-2,4, 6(1H, 3H, 5H)-trione), 1,3,5-tris(6-isocyanatohexyl)(( 1,3,5-tris(6-isocyanatohexyl))); Urea (HDI biuret) such as 1,3,5-Tris(6-hydroxyhexyl)biuret triisocyanate. Furthermore, the compound C may also be cyanate salts, such as potassium cyanate, sodium hydride, or cyanamide.

As mentioned above, in addition to the above-mentioned compound C, the second composition further includes any one or more components of a solvent, a catalyst, a physical property modifier, a dispersant, a cosolvent, and a coloring agent.

According to the creative idea of the present invention, the catalyst can be dibutyltin dilaurate (DBTDL), triethylenediamine, stannous octoate (Stannous Octoate), dioctyltin dilaurate (Dioctyltin dilaurate), methanesulfonic acid One or more of bismuth (Bismuth methansulfonate) and bismuth carboxylate (Bismuth Carboxylate).

In addition, according to the creative idea of the present invention, the physical property modifier can be polyols, such as Ethylene glycol, Diethylene glycol, Glycerol, 1,4 -1,4-Butylene glycol, 1,6-hexanediol, Tripropylene glycol, trimethylolpropane, ‎Pentaerythritol; It can also be a polyether polyol (‎Polyether polyol), such as polyethylene glycol (PEG), polypropylene glycol (PPG), polytetramethylene ether glycol (PTMG); or polyester Polyols (PE), including aliphatic polyester polyols and aromatic polyester polyols.

In addition, the colorant may be a pigment containing carbon black, white pigment, red pigment, or yellow pigment, etc., so that coloring can be completed simultaneously during the 3D printing process.

The external heating source used in the embodiment of the present invention is a near-infrared light heater with a wavelength of 1 μm to 700 nm, but it is not limited to this, and a resistance heater or an electromagnetic heater can also be used, and the ambient temperature is controlled to be in the first a temperature.

Furthermore, in order to make the first composition and the second composition fully react, the weight ratio of the molding material in the first composition to the compound C in the second composition is generally 1:1 to 10: between 1; preferably between 1:1 and 5:1; more preferably between 1:2 and 1:3.

In addition, in the cooling step S4, the external heating source is removed after a reaction time, so that the main body layer is cooled down and solidified to form, that is, the printing of a single layer is completed. The reaction time is generally between 0.05 seconds and 100 seconds; preferably between 0.05 seconds and 80 seconds; more preferably between 0.1 seconds and 70 seconds; most preferably between 0.1 seconds and 50 seconds

According to the creative idea of the present invention, the first temperature is generally lower than the melting point of the first composition, and the difference between the first temperature and the melting point of the first composition is preferably between 10°C and 100°C ; more preferably between 10°C and 80°C; most preferably between 10°C and 50°C. In addition, the second temperature is generally higher than the melting point of the first composition, and the difference between the second temperature and the melting point of the first composition is preferably between 10°C and 100°C; more preferably at Between 10°C and 80°C; optimally between 10°C and 50°C.

Hereinafter, the present invention will be further described with specific examples. "Analysis of Thermal Properties of Polyamide PA-12"

First, a differential scanning calorimeter (DSC) was used to perform non-isothermal scanning on the first composition polyamide PA-12 powder to identify the thermal properties of the PA-12 powder. The heating scan speed used is 5 °C/min, and the scanning is from room temperature to 200 °C, and the sample must be annealed under the same conditions. The non-isothermal scanning DSC curve of PA-12 is shown in Figure 3. And the thermal property data of the polyamide obtained after the sample is annealed are recorded in Table 1.

Table 1 sample Onset Tm (℃) Peak Tm (℃) Total melting heat (J/g) PA-12 165.68 174.01 58.07 165.95 174.11 52.69 171.62 177.91 52.70 average value 167.8±2.7 175.3±1.8 54.5±2.5

It can be known from the thermal property analysis in Table 1 and Figure 2 that the melting point of PA-12 used in this case is about 175°C. The experimental results of this part can help to design the first temperature used in the 3D printing process. The DSC analysis experiment of the exothermic polymerization reaction of PA-12 and the second composition will be carried out at 160, 165, and 180 °C as the first temperature. "Constant Scanning Analysis of the Second Composition Containing Catalyst and Polyamide PA-12 Powder"

PA-12, H ₁₂ -MDI, and N-methylpyrrolidone (NMP) containing dibutyltin dilaurate (DBTDL) were mixed uniformly in the weight ratio shown in Table 2, and the mixture was uniformly mixed as shown in Table 2. Under the indicated temperature conditions, a constant temperature scan was performed with a Differential Scanning Calorimetry (DSC), and the exothermic peak time of each sample and the exothermic heat of the sample were recorded in Table 2. The reactive fusion agent H ₁₂ -MDI is dissolved in butanone (MEK) (the preparation concentration is 30 wt%).

Table 2 sample Composition ( weight ratio ) Temperature ( ℃ ) Peak time (min) Heat (J/g) ^a Heat (J/g) ^b PA-12 second composition H ₁₂ MDI DBTDL/NMP 1 1 1 4× ^10-3 /0.396 160 2.39 10.39 24.94 2 2 1 4× ^10-3 /0.396 1.75 ^9.01c 27.39 3 3 1 4× ^10-3 /0.396 1.70 ^7.47c 32.87 4 4 1 4× ^10-3 /0.396 1.16 13.47 72.74 5 5 1 4× ^10-3 /0.396 1.01 16.93 108.35 6 2 1 0 1.97 27.22 81.66 7 3 1 0 1.85 24.33 97.32 8 2 1 4× ^10-3 /0.396 165 1.83 6.60 22.44 9 3 1 4× ^10-3 /0.396 1.56 10.93 48.09 10 2 1 0 2.47 33.65 100.95 11 3 1 0 1.90 30.76 123.04 12 2 1 0 180 1.41 26.43 79.29 ^a Total heat per g sample (PA- ₁₂ +H ₁₂ MDI) ^b Total heat per g H ₁₂ MDI ^c Observed from the DSC curve melting phenomenon

Figure 3 is a comparison diagram showing the constant temperature scan curves of samples 1 to 5. It can be seen from Figure 3 that PA-12 and H ₁₂ -MDI exhibit a relatively fast exothermic reaction when a catalyst is added. In addition, when observing the comparison charts of the constant temperature scanning curves of samples 1 to 5 alone, it can be observed that samples 2 and 3 have signs of partial melting of PA-12 after the exothermic reaction, as shown in Figure 4 and Figure 5, respectively; 6 shows the exothermic heat of the reaction between PA-12 and H ₁₂ -MDI in samples 1 to 5 (Total heat per g sample (PA-12+H ₁₂ MDI)), and the reaction exotherms of sample 2 and sample 3 are respectively are 9.01J/g and 7.47J/g, and the reaction heats of sample 1, sample 4, and sample 5 are 10.39J/g, 13.47J/g, and 16.93J/g, respectively. From this, it can be seen that sample 2 and sample 3 The reaction between PA-12 and H ₁₂ -MDI was disturbed by the melting of PA-12 and exhibited a lower exothermic heat. However, this phenomenon was not observed in sample 1, sample 4 and sample 5, so the weight ratio of PA-12/H ₁₂ -MDI plays an important role when using PA-12 powder as the component of the first composition , preferably using the formula of PA-12/H ₁₂ -MDI = 2/1 or 3/1.

Next, please refer to FIG. 7 , which is a comparison diagram of the constant temperature scan curves of PA- ₁₂ , sample 2, and sample 6 showing 100%; No chemical reaction occurs at 160°C. In addition, in sample 2 with DBTDL/NMP added, the total heat released by the reaction of PA-12 and H ₁₂ -MDI is smaller than that of sample 6 without DBTDL/NMP added, but the reaction rate of sample 2 It is faster than sample 6 without DBTDL/NMP added, which may be due to some PA-12 melting phenomenon interference. This phenomenon is shown in the comparison chart of the constant temperature scanning curve of sample 3 and sample 7 shown in FIG. 8 , the comparison chart of the constant temperature scanning curve of sample 8 and sample 10 shown in FIG. 9 , and the comparison chart of sample 9 shown in FIG. 10 . , and the constant temperature scanning curve comparison chart of sample 10 can be observed, showing that the effect of adding catalyst (DBTDL/NMP) on the reaction of PA-12 and H ₁₂ -MDI will not be affected by the ratio of PA-12 and H ₁₂ -MDI or The reaction temperature can effectively improve the reaction rate.

Also, please refer to FIG. 11 , which is a comparison diagram showing the constant temperature scan curves of sample 6 , sample 10 , and sample 12 . It can be seen from Figure 11 that among sample 6, sample 10, and sample 12, sample 12 has the fastest reaction, sample 10 is the second, and sample 6 is the slowest; therefore, in the case of no catalyst (DBTDL/NMP) added Under the same ratio, the reaction rate of PA-12 and H ₁₂ -MDI increases with the increase of reaction temperature. "Non-isothermal Scanning Analysis of the Second Composition Containing Catalyst and Polyamide PA-12 Powder"

After mixing PA-12, H ₁₂ -MDI, and N-methylpyrrolidone (NMP) containing dibutyltin dilaurate (DBTDL) in the weight ratio shown in Table 3, the differential scanning amount A calorimeter (Differential Scanning Calorimetry, DSC) was used to perform non-isothermal scanning, and the obtained data results were recorded in Table 3.

table 3 sample Composition ( weight ratio ) Exothermic _ Endothermic _ PA-12 second composition Onset T ( ℃ ) Peak T ( ℃ ) Heat ^a (J/g) Heat ^b (J/g) Onset T ( ℃ ) Peak T ( ℃ ) Total melting heat (J/g) H ₁₂ MDI DBTDL /NMP 13 2 1 0 103.18 130.89 11.02 33.06 149.84 166.68 66.75 14 2 1 4×10 ^-3 / 0.396 61.53 98.75 62.87 213.76 141.88 163.65 64.36 15 3 1 0 101.06 132.62 18.61 74.44 150.13 168.09 72.61 16 3 1 4×10 ^-3 / 0.396 62.31 98.45 47.77 210.19 146.65 167.39 83.48 ^aTotal heat per g sample (PA- ₁₂ +H ₁₂ MDI) ^bTotal heat per g H ₁₂ MDI

Please refer to the data in Table 3 together with FIGS. 12 and 13 . FIG. 12 is a comparison diagram showing the non-isothermal scanning curve of sample 13 and sample 14 , and FIG. 13 is a comparison diagram showing the non-isothermal scanning curve of sample 15 and sample 16 .

From Table 3, Figure 12 and Figure 13, it can be seen that the sample 14 and sample 16 with the added catalyst (DBTDL/NMP) exhibit a very fast exothermic reaction, and the onset temperature (onset temperature) and exothermic reaction peak temperature ( peak temperature) were much lower than those of Sample 13 and Sample 15 without catalyst. In addition, from the data results in Table 3, it can also be observed that the total heat release of samples 14 and 16 with catalyst is also much greater than that of samples 13 and 15 without catalyst. These experimental data show that the addition of catalyst (DBTDL/NMP) Contributes to 3D inkjet printing speed.

Also, it is worth noting that the initial melting temperature of PA-12 in sample 14 with catalyst and sample 16 is lower than that of sample 13 without catalyst and sample 15, which confirms the existence of catalyst Whether it can be used to control the mechanical properties of polymers. "The Constant Temperature Scanning Analysis of the Second Composition Containing a Physical Property Adjuster and Polyamide PA-12 Powder"

PA-12, H ₁₂ -MDI, and PEG-400 were mixed uniformly at the weight ratio shown in Table 4, and the temperature conditions were shown in Table 4 with Differential Scanning Calorimetry (Differential Scanning Calorimetry, DSC) After performing the isothermal scan, the exothermic peak time for each sample, and the exothermic heat, are recorded in Table 4.

Table 4 sample Composition ( weight ratio ) temperature (℃ ) Peak time (min) Heat (J/g) ^a Heat (J/g) ^b PA-12 second composition _H12 -MDI PPG-400 17 2 0.40 0.60 160 1.92 36.91 110.73 18 2 0.40 0.60 165 1.97 49.27 147.81 19 2 0.24 0.76 180 1.99 12.68 38.04 20 2 0.40 0.60 2.05 22.94 68.82 twenty one 2 0.56 0.44 1.77 25.68 77.04 twenty two 2 1 0 1.41 26.43 79.29 ^a Total heat per g sample (PA- ₁₂ +H ₁₂ MDI+PPG-400) ^b Total heat per g H ₁₂ MDI+PPG-400 +PPG-400)

Please refer to the data in Table 4 in conjunction with FIGS. 14 and 15 . FIG. 14 is a comparison chart showing the constant temperature scan curves of sample 17, sample 18, and sample 20, and FIG. 15 is a comparison chart showing the constant temperature scan curves of samples 19 to 22. .

From Table 4 and Figure 14, it can be seen that the exothermic peak times of Sample 17, Sample 18, and Sample 20 are 1.92, 1.97, and 1.99 minutes, respectively, indicating that the reaction can still be made in 2 without adding a catalyst. within minutes. In addition, the reaction exotherm of sample 20 was 22.94 J/g, which was significantly lower than the 36.91 J/g and 49.27 J/g of sample 17 and 18, which may be caused by the interference of partial melting of PA-12.

Furthermore, it can be seen from Table 4 and Figure 15 that, compared with the results of sample 22, the reaction rates of samples 19 to 21 all showed lower reaction rates; and as the content of PPG-400 increased, the reaction rates and total The calorific value decreased significantly.

Next, the appearance of the molded products of the samples 17 to 22 after the reaction was observed, the molded products of the samples 17 and 18 were loose in structure and could not be extended; while the samples 19 to 22 were under the same temperature condition (180°C), the samples after the reaction were completed. The extensibility of PEG-400 increases with increasing PEG-400 content. From this, it can be seen that further adding a physical property modifier (eg PEG-400) to the second composition can change the physical properties of the sample, thereby producing a multi-purpose composite polymer material by printing. "The Constant Temperature Scanning Analysis of the Second Composition Containing Catalyst and Thermoplastic Polyurethane TPU (Powder)"

First, the melting point of the TPU polymer powder used in the present invention was confirmed. Differential scanning calorimetry (DSC) was used to scan the TPU powder at a non-constant temperature, and the scanning speed was 5 °C/min, from room temperature to 250 °C, and the samples had to be annealed under the same conditions. ) Actions. The non-isothermal scanning DSC curve of TPU is shown in FIG. 16 . And the thermal property data of polyamide obtained after the sample is annealed are recorded in Table 5.

table 5 sample Onset Tm (℃) Peak Tm (℃) Total melting heat (J/g) TPU 113 143 6.16

From Table 5 and Figure 17, the thermal property analysis shows that the melting point of TPU is about 143°C. The experimental results in this part can help design the sample preheating temperature used in the 3D printing process. Therefore, 90 °C was used as the first temperature for the analysis of the exothermic polymerization reaction of the TPU powder and the second composition.

Next, TPU, H ₁₂ -MDI, and N-methylpyrrolidone (NMP) containing dibutyltin dilaurate (DBTDL) were mixed uniformly in the weight ratio shown in Table 6, and the mixture was heated at 90° C. Temperature Conditions After constant temperature scanning was performed with a Differential Scanning Calorimetry (DSC), the exothermic peak time (peak time) and exothermic heat of each sample were recorded in Table 6.

Table 6 sample Composition ( weight ratio ) T ( ℃ ) Peak time (min) Heat (J/g) ^a Heat (J/g) ^b TPU second composition H ₁₂ MDI DBTDL/NMP twenty three 1 1 4× ^10-3 /0.396 90 0.80 36.49 87.58 twenty four 2 1 4× ^10-3 /0.396 0.93 52.17 177.38 25 3 1 4× ^10-3 /0.396 1.07 42.31 186.16 ^a Total heat per g sample (TPU+H ₁₂ MDI) ^b Total heat per g H _{12 MDI}

Please refer to the data in Table 6 in conjunction with FIG. 17 . FIG. 17 is a comparison diagram showing the isothermal scan curves of Sample 23, Sample 24, and Sample 25.

It can be seen from Table 6 and Figure 17 that the exothermic front times of samples 23, 24, and 25 are 0.8, 0.93, and 1.07 minutes, respectively, which are all shorter than the reaction times of PA-12 and H ₁₂ -MDI in the aforementioned samples 1 to 22 , and the required reaction temperature is lower, showing that the reaction with TPU and H _{12 -MDI is better and more economical than the reaction with PA-12 and H 12 -MDI} when a catalyst is added for the reaction. energy.

Next, according to the above analysis results, the 3D inkjet printing test of the present invention is carried out. "Preparation Examples 1 to 4" (preparation of the second composition)

H ₁₂ -MDI, butitrone (MEK), N-methylpyrrolidone (NMP) containing 1% dibutyltin dilaurate (DBTDL), and PEG-400 were combined in the weights shown in Table 7. The percentages were mixed uniformly to obtain the second compositions P1, P2, P3, and P4, respectively.

Table 7 Preparation Example 1 Preparation Example 2 second composition P1 P2 H ₁₂ -MDI (wt%) 30 15 MEK(wt%) 70 70 1%DBTDL/NMP(wt%) 0 0 PEG-400(wt%) 0 15 physical property Viscosity (cP) 1.59 0.66 "Examples 1 and 2"

Polyamide 12 (PA-12 for short) was used in Examples 1 and 2; Supplier: Sinterit; Model: PA12 Smooth; the powder contained carbon black, with a particle size range of 20-100 µm, an average particle size of 38 µm, and a melting point of 182 °C , softening point 170 ℃) as a component of the first composition. The 3D printing machine used is modified on the basis of the ComeTrue T10 machine system of Yanneng Technology Company. As the driver, it is equipped with the SINLETAL INK 51645A hot-bubble printhead ink cartridge which integrates the hot-bubble printhead and the ink cartridge, and uses 4 near-infrared light heaters (voltage 110 V, power max 1 kW, wavelength 1 µm, effective heating area length 80 mm) for heating operation.

The PA-12 was placed on the forming platform of the 3D printing machine, and rolled back and forth with a roller to form the PA-12 into a main layer with a uniform thickness. The thickness and unit density of the main layer are shown in Table 8. Then, the main body layer was heated to the first temperature shown in Table 8 with a near-infrared light heater.

Next, the second composition shown in Table 8 was uniformly sprayed onto a specific area on the surface of the main body layer with a hot-bubble nozzle to carry out cross-linking polymerization exothermic reaction, the area of the specific area was 25mm×25mm, and the spraying amount was 20mg , the weight ratio of PA-12 in the specific region to H ₁₂ -MDI in the second composition (PA-12:H ₁₂ -MDI) was 67:33.

After the reaction time as shown in Table 8, the specific area in the main body layer becomes molten, and then the near-infrared light heater is turned off, so that the specific area will be cooled and solidified to form a single-layer three-dimensional object. After repeating the above steps three times, the finished products S1 to S4 are obtained, the time required to complete the finished products S1 to S4 is recorded respectively, and then the printing speed is converted, and then the tensile modulus of elasticity, breaking strength and elongation at break of the finished products S1 to S4 are tested, and Fill in the values in Table 8. "Comparative Example 1"

In Comparative Example 1, the same PA-12 as in the previous Examples 1 and 2 was used as the component of the first composition for 3D printing, but the second composition P1 or the second composition P2 was not used, and other 3D printing was carried out. The conditions are the same as in Example 1, and a finished product T1 is obtained, and the printing speed is converted after recording the time required to complete the finished product T1. Next, the tensile modulus of elasticity, breaking strength and elongation at break of the finished product T1 were tested, and the values were filled in Table 8.

Table 8 Comparative Example 1 Example 1 Example 2 first composition PA-12 PA-12 PA-12 second composition - P1 P2 3D printing conditions Main layer thickness (mm) 0.1 0.1 0.1 Main layer unit density (g/cm ³ ) 0.45 0.45 0.45 Second composition print volume - 20mg 20mg Printing voltage (V) - 11.04 11.04 Print Pulse (µs) - 4 4 Printing resolution (dpi) - 600 600 The first temperature (℃) 180 170 170 Response time (s) 40 30 30 Printing speed (mm/s) - 15 15 finished product T1 S1 S2 Finished Mechanical Properties Elastic modulus (MPa) 141 47 68 Ultimate tensile strength (MPa) 14.41 3.17 14.6 Elongation at break (%) 10.18 6.66 21.22

From the results in Table 8 above, it can be seen that the ultimate tensile strength of the finished product T1 after molding is 14.41Mpa, and the elongation is 10.18%; while the ultimate tensile strength of the finished product S2 after molding is 14.6Mpa, which is similar to the control group, but the extension of the finished product S2 is 14.6Mpa. The rate was 21.22%, a significant increase of about 208% compared with the control group. In addition, the ultimate tensile strength of the finished product S1 after molding is 3.17Mpa, which is about 78% lower than that of the finished product T1, and the elongation of the sample 22 is 6.66%, which is about 35% lower than that of the finished product T1. Since the ultimate tensile strength and elongation of the finished product S1 and the finished product S2 are significantly different, it shows that further adding a physical property modifier (such as PEG-400) to the second composition can change the physical properties of the sample, so as to produce a multi-purpose composite polymer materials. In addition, please refer to FIGS. 18A to C, FIG. 18A is the SEM image of the PA12 when the PA12 has not been heated, FIG. 18C is the SEM image of the finished product T1, and FIG. 18C is the SEM image of the finished product S2; from FIG. 18B, the shape of the finished product T1 can be seen Similar to the unheated PA12 in FIG. 18A , no obvious sintering occurs, and it can be seen from FIG. 18B that the finished product S2 has obvious sintering, thereby changing the overall mechanical properties.

In addition, in Example 1 and Example 2, the 3D printing only needs to be heated to 170°C, while the comparative example 1 needs to be heated to 180°C, which shows that the 3D printing method of the present invention can effectively utilize the heat of chemical reaction As a part of the heat source for melting the main body layer, the heat of the external heating source is reduced to achieve the effect of energy saving.

The embodiments of the present invention have been described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific embodiments, which are merely illustrative rather than restrictive. Under the inspiration of the present invention, without departing from the spirit of the present invention and the scope protected by the scope of the patent application, many forms can be made, which all belong to the protection of the present invention.

S1~S4: Steps

FIG. 1 is a standard flow chart showing the high-speed 3D inkjet printing of the present invention. FIG. 2 is a graph showing the comparison of non-isothermal scanning curves of PA-12 in the embodiment of the present invention. FIG. 3 is a comparison diagram showing the constant temperature scan curves of samples 1 to 5 of the present invention. FIG. 4 is a comparison diagram showing the constant temperature scanning curve of the sample 2 of the present invention. FIG. 5 is a comparison diagram showing the constant temperature scanning curve of the sample 3 of the present invention. FIG. 6 is a graph showing the comparison of the exothermic heat of the reaction of PA-12 and H12-MDI in samples 1 to 5 of the present invention. FIG. 7 is a graph showing the comparison of the constant temperature scan curves of Sample 2 and Sample 6 of the present invention. FIG. 8 is a graph showing the comparison of the constant temperature scan curves of Sample 3 and Sample 7 of the present invention. FIG. 9 is a graph showing the comparison of the constant temperature scan curves of the sample 8 and the sample 10 of the present invention. FIG. 10 is a graph showing the comparison of the constant temperature scan curves of the sample 9 and the sample 10 of the present invention. FIG. 11 is a graph showing the comparison of constant temperature scan curves of Sample 6, Sample 10, and Sample 12 of the present invention. FIG. 12 is a graph showing the comparison of the non-isothermal scanning curves of the sample 13 and the sample 14 of the present invention. FIG. 13 is a graph showing the comparison of the constant temperature scan curves of the sample 15 and the sample 16 of the present invention. FIG. 14 is a graph showing the comparison of isothermal scan curves of Sample 17, Sample 18, and Sample 20 of the present invention. FIG. 15 is a graph showing the comparison of isothermal scanning curves of samples 19 to 22 of the present invention. FIG. 16 is a comparison diagram showing the non-constant temperature scanning curve of TPU in the embodiment of the present invention FIG. 17 is a graph showing the comparison of isothermal scan curves of Sample 23, Sample 24, and Sample 25 of the present invention. 18A to C are SEM images showing PA12, finished product T1, and finished product S2, respectively.

S1~S4: Steps

Claims (10)

A 3D inkjet printing method, comprising: preheating step: using an external heating source to heat a main body layer composed of a first composition to a first temperature; the thickness of the main body layer is between 10 μm and 500 μm Between 0.1 and 1.0 g/cm 3 , the unit density is between 0.1 and 1.0 g/cm ³ , and the first temperature is less than the melting point of the first composition; the temperature rise step: apply a second composition on the main body layer at the first temperature A cross-linking polymerization exothermic reaction is carried out on the surface, so that the main body layer is heated to a second temperature to become a molten state; and a cooling step: the main body layer in the molten state is cooled and cooled to solidify and form; wherein the first composition at least comprises a component Profile, which is compound A with chemical structure represented by chemical formula (I), compound B with chemical structure represented by chemical formula (II), or polyamine compound:

(I);

(II); In the above chemical formulas (I) and (II), R ₁ , R ₂ , R ₃ , and R ₄ each independently represent an alkyl group or an aromatic hydrocarbon group; The second composition at least comprises a group having O= C=N-functional compound C, and the weight ratio of the molding material to the compound C in the main body layer is between 1:1 and 10:1; the printing method uses the heat of chemical reaction as a A portion of the heat source of the bulk layer is melted, thereby reducing the heat of the external heat source. The 3D inkjet printing method as claimed in claim 1, wherein the difference between the first temperature and the melting point of the first composition is between 10°C and 100°C. The 3D inkjet printing method as claimed in claim 1, wherein the second temperature is greater than the melting point of the first composition. The 3D inkjet printing method according to claim 1, wherein the second composition further comprises at least one selected from the group consisting of catalysts, physical property modifiers, dispersants, cosolvents, and colorants. The 3D inkjet printing method according to claim 4, wherein the catalyst is dibutyltin dilaurate (DBTDL). The 3D inkjet printing method according to claim 4, wherein the physical property modifier is at least one selected from polyols, polyether polyols, polyester polyols, and combinations thereof. The 3D inkjet printing method according to claim 1, wherein in the heating step, any one of a flat coating method, a sputtering method, a spray coating method, a casting coating method, a roll coating method, and a bar coating method is used The method coats the second composition on the surface of the first composition. A kit for 3D printing, comprising: a first composition, which comprises at least one molding material, the molding material is a compound A with a chemical structure represented by chemical formula (I), and a compound A with chemical formula (II) ) represented by the chemical structure of compound B, or polyamine compounds:

(I);

(II); In the above chemical formulas (I) and (II), R ₁ , R ₂ , R ₃ , and R ₄ each independently represent an alkyl group or an aromatic hydrocarbon group; and a second composition, the second combination The compound at least includes a compound C having an O=C=N-functional group, and the weight ratio of the molding material in the first composition to the compound C in the second composition is 1:1 to 10: between 1. The kit for 3D printing according to claim 8, wherein the second composition further comprises at least one component selected from the group consisting of catalysts, physical property modifiers, dispersants, cosolvents, and colorants. The kit for 3D printing according to claim 9, wherein the catalyst is dibutyltin dilaurate (DBTDL), and the physical property modifier is polyols, polyether polyols, polyester polyols, and at least one of its combinations.

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